Derivative Instruments, Hedging Activities and Fair Value (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Fair value measurements recurring | Level 2
Assets
Foreign currency forward exchange contracts	$ 3,781		$ 1,256
Cross-currency interest rate swaps	24,046		26,001
Liabilities
Foreign currency forward exchange contracts	2,815		3,284
Cross-currency interest rate swaps	17,412		13,410
Unit Adjustment Liability, Infrastructure Transaction [Member]
Fair value of financial instruments
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	103,308	[1]	106,343
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(5,580)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Accretion Expense	$ 2,546	[2]

[1] Does not total due to rounding.

[2] See Note 5, Equity Method Investments, for additional information related to the unit adjustment liability.